Why can't I access the public variables of the children class of TestItem in this syntax? I only have access to TestItem variables

 using UnityEngine;
 using System.Collections;
 
 public class TestBuffItem : TestItem {
 
     Hashtable buff;
 
     public TestBuffItem()
     {
         //initialize hashtable
         buff = new Hashtable();
     }
 
     public TestBuffItem(Hashtable ht)
     {
         buff = ht;
     }
 
     public void AddBuff(TestBaseStat stat, int amount)
     {
         buff.Add(stat.Name, amount);
     }
 
     //how many buffs on item
     public int BuffCount()
     {
         return buff.Count;
     }
 
     //getters and setters
     public Hashtable Buff
     {
         get { return buff; }
         set { buff = value; }
     }
 
 }

 using UnityEngine;
 using System.Collections;
 
 public class TestWeapon : TestBuffItem {
 
     int _phyDmg;
     int _magDmg;
     //the combo differs depending on attack type
     AttackType _atkType;
     //if its 2 handed weapon u cnt equip a shield
     bool _isTwoHanded;
 
     public TestWeapon()
     {
         _phyDmg = 0;
         _magDmg = 0;
         _atkType = AttackType.Sword;
         _isTwoHanded = false;
     }
 
     #region getters and setters
     public int PhyDmg
     {
         get { return _phyDmg; }
         set { _phyDmg = value; }
     }
 
     public int $$anonymous$$agDmg
     {
         get { return _magDmg; }
         set { _magDmg = value; }
     }
 
     public AttackType AtkType
     {
         get { return _atkType; }
         set { _atkType = value; }
     }
 
     public bool IsTwoHanded
     {
         get { return _isTwoHanded; }
         set { _isTwoHanded = value; }
     }
     #endregion
 
 }
 
 public enum AttackType
 {
     Sword,
     Bow,
     Staff
 }

the code works fine. i just want to assign the variable _atkType in the CreateItemDatabase() function itself. it creates the items and they are useable in my game but i can't access any variables other thn the TestItem variables. TestWeapon inherits from TestBuffItem which inherits from TestItem but only the TestItem variables are accessible. I can't even add buffs to my weapon or any other TestItem child(TestConsumable inherits TestBuffItem inherits TestItem)